Composite structural components are typically made of a polymer matrix composite material, often a fibre-reinforced polymer matrix composite material using glass and/or carbon fibre reinforcement, e.g. carbon fibre reinforced polymer (CFRP). Composite structural components offer the opportunity for lightweight and cost effective load transmission solutions. The largest benefits are often achieved when the load path and geometry are simple. Axial load transmission components, for example beams, rods, tubes and struts, are ideal candidates for polymer matrix composite material and such composite structural components are increasingly being used on commercial aircraft in addition to automotive and construction industries. These composite structural components generally require an end fitting having a complex form to interface with other components. Metals are efficient in terms of weight and cost for forming an end fitting having a complex geometry. However, joining a composite structural component to a metallic end fitting poses significant challenges, especially in the aerospace industry where the joint must be formed in a robust and certifiable manner.
Joining an end fitting to a composite structural component requires a reliable mechanism to transfer axial loads into the composite structural component. A mechanical joint may be preferred at least for aerospace certification purposes. However mechanical joints can often suffer from the problem of fretting and wear due to relative movement between the metal end fitting and the relatively soft material of the composite structural component. Sophisticated manufacturing capability may also be required to make a suitable mechanical joint.
The present disclosure seeks to provide a mechanical joint for a composite structural component which may not experience wear and damage from fretting. The present disclosure also seeks to provide a mechanical joint for a composite structural component which may have an increased strength to weight ratio and an increased strength to cost ratio.